Question: How do you artificially manipulate proteins?

Sandra Greive answered on 6 Mar 2017:

Proteins can be manipulated at several levels. They can be manipulated at the genetic level by modifying the DNA code that controls which amino acids are used where. At the protein level, proteins can be altered by other protein enzymes or by specific chemical reactions. We use enzymes that cut the protein into specific parts or extend the protein by adding peptides to the end of the protein chain. Other enzymes add or remove specific chemical tags to particular amino acids such as phosphate groups, sugars (glycosylation), and ubiquitin. Chemical biology is where we target a chemical reaction to a specific amino acid group (such as the Sulfur on Cysteine amino acids) to add things like fluorescent labels that light up under a microscope.